Ultrafast enzymatic digestion of proteins by microdroplet mass spectrometry

Xiaoqin Zhong, Hao Chen, Richard N. Zare

Research output: Contribution to journalArticlepeer-review

71 Scopus citations


Enzymatic digestion for protein sequencing usually requires much time, and does not always result in high sequence coverage. Here we report the use of aqueous microdroplets to accelerate enzymatic reactions and, in particular, to improve protein sequencing. When a room temperature aqueous solution containing 10 µM myoglobin and 5 µg mL−1 trypsin is electrosonically sprayed (−3 kV) from a homemade setup to produce tiny (∼9 µm) microdroplets, we obtain 100% sequence coverage in less than 1 ms of digestion time, in sharp contrast to 60% coverage achieved by incubating the same solution at 37 °C for 14 h followed by analysis with a commercial electrospray ionization source that produces larger (∼60 µm) droplets. We also confirm the sequence of the therapeutic antibody trastuzumab (∼148 kDa), with a sequence coverage of 100% for light chains and 85% for heavy chains, demonstrating the practical utility of microdroplets in drug development.

Original languageEnglish (US)
Article number1049
JournalNature communications
Issue number1
StatePublished - Dec 1 2020

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • General Biochemistry, Genetics and Molecular Biology
  • General Physics and Astronomy


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